THE FAMILIES AND GENEKA OF BATS. 
189 
of the others. Upper canine very small; its shaft about equal in 
height to large premolar, strongly flattened on inner surface; its 
posterior cutting edge with well-developed secondary cusp slightly 
below middle; its well-developed cingulum forming a conspicuous 
anterior basal cusp and a smaller posterior one. Lower canine even 
more reduced, closely resembling pm 3 in both size and form, except 
that its apex is less sharply pointed. The shaft is terete and the 
cingulum, though well developed, forms less distinct basal cusps 
than in the upper canine. Anterior upper premolar (pm 3 ) about 
half as high as canine, but resembling it in form even to the presence 
of the two cingulum cusps and the secondary cusp on posterior cut- 
ting edge. The shaft is, however, relatively lower and the small 
cusps are not as well developed. Posterior upper premolar, with 
inner cusp narrow, but high and very distinct, cingulum forming a 
sharp, somewhat recurved, antero-external cusp. Lower premolars 
alike in form, except that the anterior (pm 2 ) has the shaft less dis- 
tinctly terete than the others. 
It is also much shorter than the 
others. Molars normal, the 
protocones high and short; no 
trace of hypocones ; m 3 with 
three fully developed commis- 
sures; lower molars with dis- 
tinct entoconids. Skull (fig. 
29) with broad, flat rostrum 
(length from frontal angle 
scarcely greater than lachrymal breadth, but fully three times depth 
at pm 3 ), deeply furrowed in median line, and conspicuously emargi- 
nated in front by large narial opening. Antorbital foramen over 
base of anterior root of pm 4 , the canal very short, its length scarcely 
exceeding that of this root. Brain case very large, its length twice 
that of rostrum; its height, including audital bull*, equal to its 
greatest breadth, and about two-thirds its length. Base of brain case 
bent upward. Palatal emargination extending forward to level of 
posterior molars. Posterior opening of antorbital canal normal. 
Audital bull* well formed, but small, covering less than half surface 
of cochle*. Externally much as in Natalus , with similarly funnel- 
shaped ears and much distorted tragus (the latter noticeably trian- 
gular), but at once recognizable by the rudimentary thumb and 
shorter tail, which ends in interfemoral membrane a little beyond 
middle. Muzzle and lips without warty processes, other than an 
angular projection on upper lip at outer edge of downwardly opening 
nostril. 
Species examined. — Furipterus horrens (F. Cuvier). 
Fig. 29.— Furipterus horrens. x 2f. 
